Signaling system



Aug. 28, 1934.

DETECTOR '2 I5 I35 l4 12. 2,2. 24-

ANT.

v. M. GRAHAM- 1,971,605

SIGNALING SYSTEM Filed Nov. 10, 1931 LEI BY :gRGIL M :gRAHAM A OR Y FILZ;

FFEQE. I

res "Pr- 7 1,971,605 SIGNALING SYSTEM Virgil M. Graham, Rochester, N.Y., assignor to Strcrnberg-Carlson Telephone Manufacturing Company,Rochester, N; Y., a corporation of 1 New York Application November-1o,1931, Serial No. 574,065

' 12 Claims. (01. 250-20)- This invention relates to signaling systemsand Referring to Fig. 1, 6 designates an antenna or more particularly toradio receiving systems. other signal collector which is linked to theinput It has been proposed to provide an automatic circuit of aradiofrequency amplifying stage insensitivity control device or compensatingmeans cluding the screen grid vacuum tube 7. The outin a radio receiverwhereby incoming signals of put of this radio frequency amplifying stageis varying signal strength are reproduced as subcoupled to a firstdetector including the vacuum stantially uniform audio signals. 7 It isWell known tube 8. As is well known, this detector and oscilthat in suchan automatic sensitivity control delator 9 functions to translate theincoming sigvice, rectifying means is provided whereby the nal at radiofrequency into a predetermined inter- 10 carrier, Wave component of anincoming signal is mediate frequency. The output circuit of thederectified to apply a regulating potential to the tector 8 is coupledto the input of an intermediate control grid of at least one of thevacuum tubes in frequency amplifying stage including the screen a highfrequency amplifying portion of the radio grid vacuum tube 10, theoutput of which amreceiver. Such a rectifier has usually taken theplifying stage is coupled by means of a trans 15 form of athree-electrode vacuum tube which is former 11 to the input circuit of asecond detector physically independent from the detector tube includingthefive element screen grid tube 12. or frequency translating device ofthe radio re- This tube includes a plate or anode 13, a screen ceiver. pv 14, a control grid 15, acathode l6, and a heater 17.1 In order toobtain a similar result, it hasalso This second detector may beconsidered as com- 20 been proposed to use certain of the electrodes ofa prising a portion operating to translate the am- 5;- multi-electrodevacuum tube for translating an plified radio signal into audiofrequencies and a incoming signal either at radio frequency or at ansecond portion serving to rectify the carrier comintermediate frequencyinto a signal ataudio freponent of the amplified signal, all "of whichwillquencies and to utilize otherelectrodes of this tube be furtherpointed out. The first portion of the to rectify the carrier componentof the incoming detector comprises the input network including signalfor the purpose of providing a controlling the control grid 15,condenser 18, secondary windpotential for regulating the automaticsensitivity ing 19 of the transformer 11, resistor 20, the upper in theamplifier portion of the radio'receiver. In portion of resistor 21, andthe cathode 16, and. 511611 an arrangement h weve the translation alsothe output network of the detector connecting to of the incoming signalat radio frequencies or the screen 14, inductance 22, the upperportionof 8 intermediate frequencies into audio frequencies by thepotentiometer 23, primary winding of the the rectifier or translatingdevice, has been effectaudio transformer :24, to the positiveterminaloof s WithOut any p fi v o e t ct y the 180 volt source, throught is source to groundspeaking, without any translationgain. a edconductor 25, and thence to the cathode 16. It

In accordance with the present invention, it is will be noted that aresistor 26 connects the con- 0 proposed to use a multi-electrode vacuumtube trol grid 15 to the grounded conductor 25, so that With-certain ofits electrodes n i in as a the control grid is maintained at apredetermined rectifier of ms Carrier wmllonent 0f t e incoming negativepotential with respect to the cathode. signal in order to develope aregulating potential It is well known that this type of the detector,in] 'celtain of the high q y pl fyi g addition-to translating theincoming signal from staeesof a radio iv w y he en itivity radiofrequency into audio frequency, effects this of a radio receiver isautomatically adjusted otranslation with a substantial translation gaincomp n t f r v y n n mi si nal tr n h more commonly referred to asamplification.

and to employ certain other electrodes of this Thesecond portion of thedetector i cludes 45 device to translate the incoming signal from eitherthe network connecting the anode 13, the secradio frequencies orintermediate frequencies into ondary winding 19 of the tr n I audiofrequencies and this translation is effected si t r 20, and theupperxportion 0f r sistor 21 with a material increase in signal gainpopularly to the cathode 16.v It will be readily recognized referred toas fl w that this portion of the detector constitutes a Fora clearerunderstanding of the invention, truerectifier which functions totranslate the reference isimade t0 draWiTflg in' wh h Fig. 1 carriercomponent of the radio signal into pulsatis. a diagrammaticshcwing of aradio receiver in ing direct current, the audio component of whichcluding the present invention, and Fig. 2 repreis filtered out by thenetworks including the consents a. modified form of second detectorwhich densers 27, 28, 29 and 30 into substantially direct may besubstituted for thatshown in Fig. 1. g current. This direct currentflowing through the It is well known that such a change in the biasingpotential on the control grid of a vacuum tube in an amplifying stageserves to' changethe amplification effected in such a stage inaccordance with such changing potential. Similarly,

this biasing potential is applied over conductor through resistor 36 andthe secondary transformer winding 37, to the control grid 39 .of

the vacuum tube 8 in the first detector. This biasing potential likewiseregulates the amplification effected in the first detector. While thisregulating potential has been disclosed as applied to the control gridsof two vacuum .tubes of a radio receiver, the invention is not limitedto such a specific arrangement, but the desired sensitivity control maybe effected in one or more vacuum tube stages in accordance with thedegree of control desired. 5

The output circuit of the second detector previously described asincluding the primary Winding of the audio transformer 24, is coupled bymeans of this transformer to an audio stage including two vacuum tubes40 and 41 which are connected in opposition, or as more commonlyreferred to, in push-pull. The output of this audio stage is linked bymeans of an audio transformer 42 to a loud speaker LS which may be ofany well-known type.

The circuit diagram of the present disclosure with the exception of theloud speaker and a suitable power device for supplying the A current orheating current as well as the 180 volt course,

.represents the detailed circuits of a radio reing condensers which havetheir rotor units 'mounted on a single adjustable shaft to efiect aceiver. However, these circuits have not been described in detail butare shown to give a proper setting for the invention. It will beunderstood however, that condensers 43, 44 and 45 are tunproper tuningof the radio receiver.

In Fig. 2 there is shown a modified form of second detector which may besubstituted for the circuit network of Fig. 1 included between thebroken lines. This form of second detector like that previously referredto, effects the translation of the amplified radio frequencies orintermediatefrequencies into the audio frequencies with a substantialtranslation gain. While the: previously mentioned detector effectsdetection by so called plate rectification, that effected in the circuitnetwork in Fig. 2 is of the type referred to as grid detection. In theoperation of this circuit network, amplified incoming signals ateitherradio frequencies or intermediate frequencies are introduced throughthetransformer 11 into the input circuit of the second detector includingthe five-element vacuum tube 12. This .input circuit may be described asincluding the cathode 16, the secondary winding 19 of the transformer11, which winding is bridged by the condenser 52, resistor 53, gridleak. 54 and grid condenser55 in paralleL'and control grid,15..

The output circuit of this detector includes the screen 14, inductance56, primary winding of the transformer 24, through the 180 volt source,ground conductor 25 and thence through resistor 53, secondary winding 19to the cathode 16. This output circuit is linked by the transformer 24to the audio amplifier including the vacuum tubes tending from the anode13, resistor 5'7, ground conductor 25 and thence to the cathode 16. Therectified carrier wave flowing through the resistor 57 develops a dropin potential which is applied through the resistor 31 and the conductor35 to the control grid or grids of one or more of the amplifying stagespreceding the second detector in a manner already described inconnection with Fig. 1. The capacitor 58 co-operates with the resistor57 to filter out the audio component of the rectified carrier wave andthe resistor 31 with the condenser 59 serves further to filter out anyundesired audio component.

While the present invention has been shown asincorporatedinaradioreceiver of the superheterodyne type, it is equallyapplicable to other type of radio receivers including those of the tunedand untuned radio frequency types. From the foregoing it will beunderstood that applicant has invented a detector in which a portionthereof translates an incoming signal into audio frequencies' with asubstantial translation gain and in which a portion of the detectordevelops a regulating potential which is utilized to controlautomatically the sensitivity of a radio receiver whereby substantiallyuniform signal volume is de- 1.1.!

Veloped.

WhatI claim is:

1. In a radio receiver utilizing a single heated source of electronemission fora plurality of electron paths, the method of reproducingradio frequency signals into perceptible condition at-uniform volumewhich comprises, amplifying said signals above audibility, translatingsaid amplified signals into audio frequency signals .with'a substantialtranslation gain through one of said electron paths, rectifying acomponent of said amplified signals through another of said paths,

utilizing said rectified signal component in regulatingthe amplificationof the signals above audi-' n bility, and translating said audiofrequency sigll";

nals into perceptible condition.

2 In a radio receiver utilizing a single heated source of electronemission for a plurality of electron paths, the method of reproducingradio frequency signals into perceptible condition at uni- I.

form volume which comprises, amplifying said signals above audibility,translating said amplifled signals into audio frequency signals with asubstantial translation gain through one of said electron paths,rectifying a component of said I1;-

amplified signals through another of said'paths,

filtering said rectified component to eliminate a substantial pulsatingcomponent therefrom, devel'oping from said rectified and filteredcomponent a regulating'potential, utilizing said po- .1

tential to regulate the amplification of signals above audibility, andtranslating said audio frequency signalsinto audible signals.

3. In a radio, receiver including an amplifier having means to regulatethe degree of amplifica- I 5 tion to be effected therein determined by abiasing potential, and a detector of the electron dis-' charge typeutilizing a single heated source of electron emission fora plurality ofelectron paths,

the method of reproducing radio frequency siggamete rceetitr ceiieitgenat endees-weenie h mifaiageisnaiaatcve armss ente ta ners-rangeansweer/re readers fr'e de lower n -sew l's'ii u tilizliif anourer eie t o ieirri'e'atv veesmp a ameesesaz spmeesigs isg asses g laureates-retri veridnlii'oliien't td difi- M velop a biasing otential, applyifi g saiwfiiasiifg 10 potr'i-tiisl t'd re ate' t'li e'signal amplificationeffected above audible frequencies, and translating said audio frequencysignals into perceptible condition. 4. In a radio receiver including anamplifier provided with means to regulate the degree of amplification tobe effected therein as determined by a biasing potential, and a detectorof the electron discharge type utilizing a single heat/ed source ofelectron emission for a plurality of elec- '20 tron paths, the method ofreproducing radio frequency signals into perceptible condition atuniform volume which comprises, amplifying signals above audibility,utilizing one electron path to translate said amplified signals intoaudio fre- 25 quency signals with an appreciable translation gain andutilizing another electron path to rectify the carrier wave component ofthe amplified signal, employing said rectified carrier Wave component todevelop a biasing potential, and applyfifiing said biasing potential tosaid amplifier to regulate the amplification effected therein, andtranslating said audio frequency signals into perceptible conditreceiver including an amplifier typ 1;. g a l0 emission for a plura 1method of reproducing 1' into perceptible conditiion at uniform volumewhich comprises, amplifying said signals above audibility, developingelectron emission from said source, utilizing a portion of said electronemission in one path to translate said amplified signal into audiofrequency signals and to amplify the same, utilizing another portion ofsaid electron emission in another path to def i velop a rectifiedcurrent corresponding to the carrier wave component of saidfirst-mentioned amplified signals, employing said rectified current togenerate a biasing potential, utilizing said biasing potential toregulate the amplification of said 35 first-mentioned signals, andtranslating said audio frequency signals into perceptible condition 6.In a radio receiver, an amplifying stage including a vacuum tubeoperating to amplify signals at frequencies above audibility, a detector(lei-Z having a vacuum tube provided with a first electrode, a secondelectroda'a third electrode, and a cathode, an input circuit for saiddetector linked to said amplifier, said input circuit including saidcathode and one of said electrodes, an output circuit including saidcathode and another of said electrodes, a rectifier circuit including aportion of said input circuit, an additional one of said electrodes andP r said cathode, said rectifier circuit serving to recti fy the carriercomponent of said amplified signal, means for developing a potentialaccording to said rectified carrier component, and means for utilizingsaid potential to control the amplification efiected in said amplifyingstage.

'7. In a radio receiver, an amplifying stage inest . l nlked tosaidianiplifier by a transformer, said saiuaiir iiryilig sta efnywtransrerme sare mput i iiicmcing ear ssumes ne seeonuary tieiiep'saietiiii'd said first e letrbde thr odgnanapaMt for biasing said thirdelectrode, an output circuit including said second electrode and saidcathode, a resistor in said input circuit, and means for applying anegative potential developed by said resistor to control theamplification effected in said amplifier.

8. In a radio receiver, an amplifying stage, including a vacuum tubeoperating to amplify signals at frequencies above audibility, a detectorhaving a vacuum tube provided with electrodes including an anode, ascreen, a control grid and a cathode, an input circuit for said detectorlinked to said amplifier by a transformer, said input circuit includingsaid cathode, the secondary winding of said transformer, a grid leak anda grid condenser in parallel and said control grid, an output circuitfor said detector including said screen and said cathode, a rectifiercircuit including said cathode, a portion of said input circuit and saidanode, means in said rectifier circuit for developing a potentialvarying in accordance with the rectified current therein, and means forapplying said potential to the control grid of said amplifier.

9, In a radio receiver, an amplifying stage includingravacuum tubeoperating to amplify sigaudibility, detector yided with "electrodesee'n, a control grid and Te i a athodefa input circuit including saidcathode, the secondary winding of said transformer, a grid leak and agrid condenser in parallel and said control grid, an output circuitincluding said screen and said cathode, a rectifier circuit includingsaid cathode, a portion of said input circuit and said anode, said inputcircuit including a capacitance bridged across the terminals of saidsecondary winding to tune said input circuit, means in said rectifiercircuit for developing a potential varying in accordance with therectified current therein, and means for applying said potential to thecontrol grid of said amplifier.

l0. Ina radio frequency signaling system, means for amplifying signalsat frequencies above audibility, means including one heated electronsource for translating said amplified signals into audio frequencysignals with a substantial trans.- lation gain, means including saidheated electron source for rectifying a component of said amplifiedsignals, means controlled by said rectified signal component andincluding a portion of said amplifying means for regulating theamplification effected by said amplifying means, and means forreproducing said audio frequency signals into perceptible form.

11. In a radio frequency signaling system, means for amplifying signalsat frequencies above audibility, means including one heated electronsource for translating said amplified signals into audio frequencysignals with a substantial transnal component, means controlled by saidfiltered quencysianals with. fiu anfla re s at n ain, meansincludingsaidheated electron source 101;- z eofl-fylngn compenentof-sglql gmplifled; signals; cqp-trplled, by said ,rectifled' signal,component fqn-pqntrolling the biasing of 'sa 1d-a .mp1i-; fying ;4-mea rls whereby the amplification eiiected: by-saisi am lit ms me nregulated, d a for reprodueingus aidnqqdio frequency signalsintoperceptible form, t I j 1 1,971,605Q-Vi'rgil Graham,- Roch August 28-3 Disclaim d M rz'zmberg-0arlson Telephonii-Mr1n 3min pateIg-erebyenters 131115 dl sclauner as to laims 3, 4, 6, 10, 1 and 12 fsaid[Ofiicial Gazette April 21, 1986.]

quencysianals with. fiu anfla re s at n ain, means includingsaidheatedelectron source 101;- z eofl-fylngn compenent of-sglql gmplifled;signals; cqp-trplled, by said ,rectifled' signal, componentfqn-pqntrolling the biasing of 'sa 1d-a .mp1i-; fying ;4-mea r lswhereby the amplification eiiected: by-saisi am lit ms me n regulated, da for reprodueingus aidnqqdio frequency signals intoperceptible form, tI j 1 1,971,605Q-Vi'rgil Graham,- Roch August 28 -3 Disclaim d Mberg-arlson Telephonii-Mr1n 3min pateIg-ereby enters 131115 dl sclauneras to-laims 3, 4, 6, 10, 1 'and 12 fsaid [Ofiicial Gazette April 21,1986.]

